Its been a while since chat was removed on the Xbox version of roblox. The game is also now rated E10+. From what I've read its because at first it was rated E for everyone so they had to remove text chat so it could fit in the age range that was allowed.
The second reason why the can't chat in Roblox error happens is related to the fact that the developers added a default system of settings. As a result, the contact settings are set to “No one” in the privacy section. Changing this setting to everyone will fix the can't chat in Roblox error.
One of the many great ways to communicate with your fellow players is to use the in-experience chat feature. To start chatting, press the / key on your keyboard. This will open up the chat window, if enabled by the developer, and a chat-bar where you can type what you would like to say.
If the person that you are trying to message has a Message button that is not clickable, then their privacy settings might not be set up to allow private messages at this time. Additionally, you will need to make sure your privacy settings would allow them to message you back.
Press the Xbox button to open the guide, and then select Parties & chat > New chat. Enter a gamertag or choose someone (or several people) from your friends list, and then select Done.
Changing Privacy and Chat SettingsLog into the account. (If you can't log in, try these steps for recovering your password.)Go to account Settings. Browser - find the gear-icon located at the upper-right corner of the site. ... Select the Privacy tab.Adjust the Contact Settings and Other Settings.
0:343:02How to Send Messages in Roblox! - YouTubeYouTubeStart of suggested clipEnd of suggested clipSelect. A friend from your friends list then type your message into the chat box and hit enter toMoreSelect. A friend from your friends list then type your message into the chat box and hit enter to send in roblox.
How to Enable a New Bubble Chat in Roblox (2021)Open your Roblox Studio.Open the game you want to add the bubble chat feature to.Head over to “Explorer” at the left of your screen.Click on “Chat.”Go to “Chat properties.” You should see a “Behaviour” tab. Click on it.You'll see a box named “BubbleChatEnabled”.